1. Field of the Invention
The present invention generally relates to an air intake structure for an internal combustion engine. More specifically, the present invention relates to an internal combustion engine air intake structure that includes an air control valve for changing the cross sectional area of an air intake passage.
2. Background Information
One known method of producing tumbling of the fuel-air mixture in a reliable manner is to provide a partition wall inside a passageway of an intake port to divide the passage into a first passage and a second passage and provide an air intake control valve (shutter valve) that can open and close the second passage. When the air intake control valve is closed, the outer edge of the air intake control valve touches against the partition wall and deflects the intake air to flow through the first passage, thereby causing a tumbling motion to occur. An example of an air intake structure employing such arrangement is disclosed in Japanese Laid-Open Patent Publication No. 7-25264.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved air intake structure for an internal combustion engine. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.